The radio station behind an ultimately tragic hoax call to the Duchess of Cambridge's hospital ward could be forced to name those who allowed the prank to be broadcast.

On Thursday Australia's media watchdog is expected to announce an investigation into the prank, according to a news website.

The independent Australian Communications and Media Authority could ultimately compel 2Day FM’s parent company Southern Cross Austereo to name the staff responsible, it reported.

The watchdog will determine whether the station breached its licensing conditions in airing the call, now linked to the suspected suicide of 46-year-old Jacintha Saldanha.

The mother-of-two was found hanged just days after forwarding a phone call from Sydney DJs Mel Greig and Michael Christian to a ward nurse at London's King Edward VII hospital, where pregnant Kate was suffering from severe sickness.

Both nurses believed they were speaking to the Queen, with Ms Greig posing as the monarch and making enquiries about her "granddaughter's" morning sickness.

Consent is critical in any defence of a taped phone call, and the radio broadcasting code stipulates that it is a breach to record a person in conversation, and also air it, without their knowledge.

Southern Cross Austereo (SCA) is to resume running adverts on 2Day FM on Thursday, following a brief suspension.

All profits the station makes from advertising until the end of the year will be donated to a memorial fund set up in aid of Ms Saldanha's family.

A minimum contribution of AUS$500,000 (£326,000) will be made, the company said.